Learn about C40’s mission, guiding principles, and the action we are taking to create a sustainable future for everyone, everywhere.

Our cities

Cities in the C40 network earn their membership through action.

Our Leadership Standards set the minimum requirements for all member cities and safeguard the integrity of C40 as a network of climate leaders.

Membership operates on performance-based requirements, not on fees, and every city in the C40 network is reviewed annually against our Leadership Standards.

C40 Leadership Standards 2021–2024:

Plan. City has adopted a resilient and inclusive climate action plan aligned with the 1.5°C ambition of the Paris Agreement, and updates it regularly;
Deliver. In 2024, city remains on track to deliver its climate action plan, contributing to increased resilience, equitable outcomes and halving C40’s overall emissions by 2030;
Mainstream. City uses the necessary financial, regulatory and other tools at their disposal to address the climate crisis and mainstreams their equitable climate targets into the most impactful city decision-making processes;
Innovate. City innovates and starts taking inclusive and resilient action to address emissions beyond the direct control of the city government, such as associated with goods and services consumed in their city;
Lead. Mayor and the city demonstrate global climate leadership and inspire others to act in support of the Paris Agreement.

C40 mayors have been at the forefront of climate leadership for over 15 years, driving the conversation around climate action and environmental justice to place these issues front and centre in our local policies and on the international agenda.